Disk drives store and retrieve data for digital electronic devices such as computers. A typical magnetic disk drive has a head, including a slider and a transducer, in very close proximity to a surface of a rotatable magnetic disk. The transducer generally includes a write element and/or a read element. As the magnetic disk rotates beneath the head, a very thin air bearing is formed between the surface of the magnetic disk and an air bearing surface of the slider. The write element and the read element can be alternately employed to write and read data while an actuator assembly positions the heads along desired magnetic “tracks” on the magnetic disk.
In order to keep the head properly oriented and at the correct height above the disk while in flight, disk drives employ a head gimbal assembly (HGA) that includes the head and a suspension that further includes a load beam and a flexure that supports the head. The flexure is attached to the load beam at one or more points but the distal end of the flexure is often unattached to allow the head on the flexure to roll (e.g., like an airplane) along a long axis of the suspension. To enable the rolling motion of the head, a protrusion from the load beam can make contact with a backside of the flexure at about a central area of the slider.
The typical flexure is a layered structure that includes a thin metal support layer, electrical traces, and an insulating layer to keep the electrical traces from contacting the metal support or each other. To electrically connect the head to the electrical traces during assembly, bonding pads of the head's transducer (e.g., slider) are soldered to corresponding termination pads of the electrical traces on the flexure. With increasing HGA complexity and the number of electrical connections to the head to enable slider recording technology within current slider form factors, the solder size is typically required to be miniaturized to pack many solder joints on the head without bridging between solder joints. However, as the solder gets smaller, it becomes more susceptible to mechanical stress and may crack if the stress is beyond the solder joint strength. In some cases, the stress and/or cracking in a solder joint can result in catastrophic connectivity failure within the disk drive.
At times, a disk drive will experience undesirable and violent non-operational shock that might be the result of sudden movement of the disk drive. As a result, the free end of the flexure may swing towards the load beam and a backside area of the flexure opposite the slider solder bonds may make forceful contact with the load beam. In such case, the solder joints on the slider may crack thereby resulting in a weakened or non-functional joint. A similar problem can occur during the roll operation when the flexure backside opposite the slider solder bonds makes contact with the load beam. As such, improved suspension assemblies for minimizing stress on the slider solder joints are needed.